const PI = 3.14159265358979324;
const xpi = (3.14159265358979324 * 3000.0) / 180.0;

export function delta(lat, lon) {
  const a = 6378245.0; //  a: 卫星椭球坐标投影到平面地图坐标系的投影因子。
  const ee = 0.00669342162296594323; //  ee: 椭球的偏心率。
  let dLat = transformLat(lon - 105.0, lat - 35.0);
  // //console.log('transformLat dLat',dLat);
  let dLon = transformLon(lon - 105.0, lat - 35.0);
  // //console.log('transformLat dLon',dLon);
  const radLat = (lat / 180.0) * PI;
  let magic = Math.sin(radLat);
  magic = 1 - ee * magic * magic;
  const sqrtMagic = Math.sqrt(magic);
  dLat = (dLat * 180.0) / (((a * (1 - ee)) / (magic * sqrtMagic)) * PI);
  dLon = (dLon * 180.0) / ((a / sqrtMagic) * Math.cos(radLat) * PI);
  return { lat: dLat, lon: dLon };
}
// GPS---高德
export function gcjEncryptta(wgsLat, wgsLon) {
  if (outOfChina(wgsLat, wgsLon)) return { lng: wgsLon, lat: wgsLat };

  const d = delta(wgsLat, wgsLon);
  const lng = Number.parseFloat(wgsLon) + Number.parseFloat(d.lon);
  const lat = Number.parseFloat(wgsLat) + Number.parseFloat(d.lat);
  return { lng: lng, lat: lat };
}

// GCJ-02 to BD-09
export function bdEncrypt(gcjLat, gcjLon) {
  const x = Number.parseFloat(gcjLon);
  const y = Number.parseFloat(gcjLat);
  const z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * xpi);
  const theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * xpi);
  const bdLon = z * Math.cos(theta) + 0.0065;
  const bdLat = z * Math.sin(theta) + 0.006;
  return { lng: bdLon, lat: bdLat };
}

export function outOfChina(lat, lon) {
  if (lon < 72.004 || lon > 137.8347) return true;
  if (lat < 0.8293 || lat > 55.8271) return true;
  return false;
}

export function transformLat(x, y) {
  let ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x));
  ret += ((20.0 * Math.sin(6.0 * x * PI) + 20.0 * Math.sin(2.0 * x * PI)) * 2.0) / 3.0;
  ret += ((20.0 * Math.sin(y * PI) + 40.0 * Math.sin((y / 3.0) * PI)) * 2.0) / 3.0;
  ret += ((160.0 * Math.sin((y / 12.0) * PI) + 320 * Math.sin((y * PI) / 30.0)) * 2.0) / 3.0;
  return ret;
}
export function transformLon(x, y) {
  let ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x));
  ret += ((20.0 * Math.sin(6.0 * x * PI) + 20.0 * Math.sin(2.0 * x * PI)) * 2.0) / 3.0;
  ret += ((20.0 * Math.sin(x * PI) + 40.0 * Math.sin((x / 3.0) * PI)) * 2.0) / 3.0;
  ret += ((150.0 * Math.sin((x / 12.0) * PI) + 300.0 * Math.sin((x / 30.0) * PI)) * 2.0) / 3.0;
  return ret;
}
